For many years, a variety of solid and semi-solid products have been packed and sold in disposable or "one-trip" containers. A recurring problem with such products so packed is that the volume of a conventional package is fixed, while the volume of the product contained diminishes as the product is consumed.
One well-known solution to this problem is to provide a reducible volume container. In such containers, the consumer removes portions of the package as he or she uses the product, so that the volume of the container diminishes with the volume of the product. Reducible volume containers have been proposed in the form of cartons having walls that are adapted to be stripped away in successive sections. Examples of such cartons are shown in the following U.S. Pat. No. 2,490,133 to Inman; U.S. Pat. No. 3,967,773 to Kaufmann; U.S. Pat. No. 4,349,110 to Hayashi; U.S. Pat. No. 4,762,233 to Sears; and U.S. Pat. No. 5,217,164 to Sullivan. Generally, these patents show cartons in which tear strips are defined by providing the carton material with weakened areas, usually in the form of lateral score lines. The tear strips terminate in some sort of tab element to be grasped by the consumer, who proceeds to remove the strips, as required, by tearing along the score lines.
Although the concept of reducible volume cartons has obvious appeal, such cartons in known configurations have not met with widespread consumer acceptance. One reason for the lack of success may be the nature of the tear strips themselves. In known reducible volume containers, the tearing process for the strips is frequently difficult to begin and unpredictable. The tab elements of the tear strips are often difficult to locate and grasp. Further, unless the consumer takes great care to tear the strip straightly and precisely along the score line, the strip has a tendency to tear across itself. When the strip tears across itself, the consumer must attempt to start and completely tear the strip adjacent to the malfunctioning strip. This renders further opening of the carton difficult at best.
It can thus be seen that the need exists for a reducible volume container in which tear strips are easy to locate and grasp, with some mechanism for lessening the tendency of tear strips to tear across themselves.